The present invention relates to an image forming apparatus favorably applied to a copying machine equipped with a control function for jobs including image forming processing and to a compound machine having a copying function, a printer function and a facsimile function.
To be more precise, the image forming apparatus of the invention is one which is equipped with a control means that controls jobs including image forming processing and executes the jobs in succession, and can execute continuously image forming processing for the reserved and registered job, when another job is reserved and registered after the job that is being executed presently, by following the recording sheet for image forming processing for the last page in the concerned job, without stopping, at each termination of the job being executed presently, the driving systems such as a developing unit, a drum and a conveyance belt all relating to the image forming processing.
Incidentally, in the invention, the job means a series of operations relating to image forming, and it covers a range from a startup operation conducted in advance to image forming operations to a termination operation conducted after the image forming operations. For example, when copying images of plural sheets of documents, a series of operations relating to plural sheets of copies are regarded as one job, and when making copies of plural sets, a series of operations relating to copies of plural sets are regarded as one job.
A digital copying machine which forms images based on image data obtained from images of a document has come to be used lately. In this copying machine, image information of a document is read by a scanner or the like, and then, image information of the document is stored temporarily in an image memory. Then, the image information stored in the image memory is subjected to image processing such as image reduction, image enlargement and image rotation, in accordance with user""s demands. Then, images based on the image data subjected to the image processing are formed on a prescribed transfer sheet by an image forming means (printer). As a result, it is possible to copy the images of the document.
Further, there is available on the market a compound machine wherein the aforesaid digital copying function, facsimile function and printer function are compounded, and a printer is shared by the aforesaid three functions, while, an image reading means (scanner) is shared by the copying function and the facsimile function.
FIG. 17 is a block diagram showing a structure example of compound machine 10 of this type. Compound machine 10 shown in FIG. 17 has data bus 1. To this data bus 1, there are connected communication modem 2, coding section 3, scanner 4, image processing section 5, data communication section 6, image memory 7, printer 8 and control section 9. To this control section 9, there are connected operation section 9A and display section 9B. In compound machine 10 of this type, image memory 7 is divided into copy area 7A and FAX area 7B.
In the copying function, the copy area 7A is used, and document image data obtained through reading by scanner 4 are compressed and then are stored. In the facsimile function, the FAX area 7B is used, and image data sent from a target are decoded by coding section 3 after being received by communication modem 2, and then, are recorded on t he FAX area 7B assigned for the facsimile function.
In the printer function, the copy area 7A is used, image data coming from a computer are subjected to prescribed image processing at image processing section 5 after being received by data communication section 6. With regard to the copy area 7A and the FAX area 7B, when capacities of both of them are compared, the greater capacity is assigned to the copy area 7A in many cases, though this is affected by easiness of operations.
The image data stored in image memory 7 are extended and then are subjected to prescribed image processing in image processing section 5 to be outputted to printer 8. In the printer 8, image data are transferred onto a recording sheet on a one page unit basis so that an image is formed. With regard to image forming processing on the recording sheet, when conducting plural print jobs continuously, print jobs are registered in a memory in advance so that each job is controlled.
For example, when the first print job is started in step D1 of the flow chart shown in FIG. 18, the driving (load) systems such as a photoreceptor drum and a conveyance motor are turned on in step D2. After that, its print job is started in step D3, and when a print for the last page concerning the aforesaid print job is completed in step D4, the driving systems are turned off. After that, when the print job is completed, it is checked, in step D7, whether the next job is registered or not. If the next job is registered, the sequence goes back to step D1, and step D2-step D6 mentioned above are executed repeatedly. If the next job is not registered, the image forming control is ended.
Incidentally, the following problems are caused by conventional compound machine 10. When conducting plural jobs continuously, productivity of images was not so good, because startup operations for the succeeding job were conducted after termination operations for the preceding job were conducted. In the case of an electro-photographic apparatus, for example, a rotation-stopping operation to stop rotation of a photoreceptor, an operation to neutralizing the surface of the photoreceptor for preventing deterioration of the photoreceptor, an operation to turn off the power supply for a charging unit and an operation to turn off the power supply for a sheet feeding motor are included in the termination operations. Further, a rotation-starting operation to start rotation of a photoreceptor, an operation to turn on the power supply for a charging unit and an operation to turn on the power supply for a sheet feeding motor are included in the startup operations. In the case of the startup operation, it requires a period of time covering from the start of rotation of the photoreceptor to the stabilization of the rotation, while, in the case of the termination operation, a period of time required for the termination operation is long because the operation is actually started after the last sheet has been ejected out of the machine completely, from the viewpoint of measures for jamming, although the time required for the termination operation only is not so long. The time required for both the startup operations and the termination operations is about 6-8 seconds in total, in the case of a copying machine of, for example, 20 30 CPM. Since this time is added when each job is switched, the total time is longer when the number of jobs to be conducted continuously is increased, thus, productivity has been reduced.
So, an object of the invention is to solve the problems stated above, and thereby to improve a control method for plural continuous jobs for image forming to provide an image forming apparatus capable of improving productivity of image forming.
Accordingly, to overcome the cited shortcomings, the abovementioned object of the present invention can be attained by an image forming apparatus, comprising: an image forming section to form an image; a sheet-feeding/conveyance section to convey a recording sheet; a controlling section to control the image forming section and the sheet-feeding/conveyance section; and a memorizing section to memorize jobs reserved for an image forming processing, wherein the image forming processing for one of the jobs includes a startup operation, an image forming operation and a terminating operation, and, when the memorizing section memorizes a next job to be executed next to a current job, which is currently executed in the image forming apparatus, the controlling section controls the image forming processing so as to perform the image forming operation for the next job succeeding to that for the current job, without performing the terminating operation for the current job and the startup operation for the next job.
Further, to solve the aforesaid problems, the image forming apparatus of the invention has therein a registration means in which plural jobs including image forming processing are registered and a control means which controls reservation of the jobs registered in the registration means and executes successively the jobs registered in the registration means, and is characterized in that the control means starts the job for registering reservation in the course of image forming processing for the last page in the concerned job, when another job is reserved and registered after the job that is being executed currently in the registration means, and controls the feeding of the first sheet in the job relating to reservation registration, following the recording sheet for image forming processing for the last page in the concerned job.
In the image forming apparatus of the invention, when plural jobs including image forming processing are registered in the registration means, reservation of the jobs registered in the registration means is controlled by the control means, and the jobs registered in the registration means are executed in succession. When another job is reserved and registered after the job being executed currently, the job relating to the reservation and registration is prepared in the course of image forming processing for the last page in the concerned job, and the feeding of the first sheet in the job relating to the reservation and registration is controlled by the control means, following the recording sheet for image forming processing for the last page in the concerned job.
Accordingly, it is possible to conduct image forming processing for the reserved and registered job continuously, following the recording sheet subjected to image forming processing for the last page in the concerned job, without stopping driving systems such as a developing unit, a drum and a conveyance belt all related to image forming processing at each termination of the job being executed currently.